The novel aldoxime of the present invention has been found to be an important industrial intermediate which can be easily converted to several important monomers. For example, by hydrogenation, the novel aldoxime can be converted into 12-aminododecanoic acid, the monomer for Nylon-12. Nylon-12 is an engineering polyamide fiber having a myriad of uses. It is often used as a curing agent for epoxy resins, a modifier for polyester materials, or by the automobile industry for the preparation of oil and gasoline resistant tubes. Nylon-12 can be used in hydraulic systems, electrical cables, metal coatings, ship propellers, screws, injection syringes, sterilized films and bags for medical purposes and foodstuffs, e.g., the skin for sausages. The properties of Nylon-12 can be readily modified by adding to it polyamide additives, including plasticizers, pigments and heat and light stabilizers.
Presently, 12-aminododecanoic acid is produced by a process involving the initial trimerization of butadiene to give cyclododecatriene. Presently, the butadiene is produced from petroleum products--either from catalytic dehydrogenation of petroleum gases, i.e., butene or a butene-butane mixture, or by cracking naphtha (C.sub.6 H.sub.14 --C.sub.7 H.sub.16) or light oil. Butadiene is then hydrogenated to cylododecane, which, in turn, is oxidized to give cylododecanol. The cylododecanol is oxidized to the corresponding ketone, then to an insoluble oxime, which gives lauryl lactam through a Beckmann rearrangement. Lauryl lactam is subsequently converted to Nylon-12 via the intermediate, 12-aminododecanoic acid.
According to the present invention, commercially important chemicals, heretofore derived from petrochemical feedstocks, are, instead, synthesized from a renewable raw material. In the present invention, a novel compound, 12-oxododecanoic acid oxime, which can easily be converted into the monomer of Nylon-12, is synthesized from vernolic acid, a naturally epoxidized C-18 fatty acid, obtained from the seed oil of Vernonia galamensis. The seed of Vernonia galamensis, an annual herb, indigenous to tropical and sub-tropical Africa, contains about 40% naturally epoxidized triglyceride oil. Upon saponification and acidification, the seed oil yields about 75-80% vernolic acid, 10-13% linoleic acid, 4-6% oleic acid, and 3-6% saturated acids, making it an abundant source of a unique and naturally epoxidized fatty acid.
Vernonia oil has been the subject of several recent studies. In one study, vernonia oil was reacted with acetic acid. By cleavage of the epoxy group, hydroxy acetate was formed, which was then saponified and methylated to obtain methyl 12,13-dihydroxyoleate. This intermediate then was oxidized with periodic acid to give methyl 12-oxo-cis-9-dodecenoate. In the present invention, a process for the direct oxidation of the epoxy group of vernolic acid, to form an oxo acid is provided. This oxo acid is a key intermediate which is subsequently converted to 12-oxododecanoic acid oxime, which can then be converted to any one of several commercial products, including, for example, 12-aminododecanoic acid.